Question

find the area of circular ring whose external and internal diameter are 20cm and 6cm respectively

Answer 1

Hope this answer will help u

Answer 2

Answer:

$\red {Area \: of\:the \: circular \:ring (A)}\green { =286\:cm^{2}}$

Step-by-step explanation:

$Given \: External \: diameter \: of \: a \\circular \: ring (D) = 20 \:cm$

$External \:Radius \: of \: the \:ring (R)\\ = \frac{D}{2} \\= \frac{20}{2} \\= 10\:cm$

$Internal \: diameter \: of \: the\\circular \: ring (d) = 6\:cm$

$Internal \:Radius \: of \: the \:ring (r)\\ = \frac{d}{2} \\= \frac{6}{2} \\= 3\:cm$

$Area \: of \:ring (A) = \pi ( R^{2} - r^{2} )\\= \frac{22}{7} ( 10^{2} - 3^{2} )\\= \frac{22}{7} ( 100 - 9 )\\= \frac{22}{7} \times 91 \\= 22 \times 13 \\= 286\:cm^{2}$

Therefore.,

$\red {Area \: of\:the \: circular \:ring (A)}\green { =286\:cm^{2}}$

•••♪